Mechanical music movements produce a distinctive sound and although originally they were expensive toys for aristocrats in Europe used to reproduce complex tunes, in modern days they normally play a short simplified tune and cost very little. The tune or tune fragment is produced by selectively plucking a plurality of reeds on a vibration plate. Modern musical movements pluck the reeds with pins which extend out of the side of a cylindrical drum which is rotated adjacent the vibration plate.
Various mechanical drivers are used to rotate the drum. For example, in very simple musical movements, the drum is rotated by means of a hand crank and a simple reduction gear. In other movements, a spring motor is included which may be wound by means of a key or a pull string. When a spring motor is provided, a transmission is included between the spring motor and the drum, which includes some sort speed regulator. The regulator can take the form of a fan whose drag increases exponentially with speed to compensate for the variations in forces applied by the spring motor between its fully wound position and its unwound position. Better speed regulation can be obtained through the use of centrifugal brake devices, which spin one or more brake shoes against a fixed drum and are arranged so that faster speeds increase the centrifugal force and cause the brake shoes to engage the drum with more force. In this way, high unwind speeds are avoided since at high speeds the braking device produces much more braking than at low speeds. However, because of cost constraints, neither of the described speed regulators are particularly accurate, they only acting to modulate unwind speed of the spring motor and not really completely control it.
Electronic musical circuits are now available at very low costs. However, such devices produce tones by electronically generating sound signals and then playing them through a speaker. In most applications, there is very little room for a speaker so that low volume and a particularly characteristic electronic sound is produced, which is not as pleasing as the sound produced by traditional mechanical musical movements. Also, mechanical musical movements can have power take off devices to actuate additional features. For example, when a mechanical musical movement is placed within a stuffed bear, a power take off can be provided to the bear's mouth. The result is a stuffed bear who appears to be singing along with the tune produced by the mechanical musical movement.
In recent times, bright multi-colored, light emitting diodes and high intensity micro incandescent lamps have become available. There are applications where it is desirable to provide light outputs at the time a mechanical musical movement is producing a tune. This is very simple to do when an electronic musical circuit is used as the required current outputs from such an electronic circuit are relatively easily implemented. However, as aforesaid, the music produced by such electronic devices is of inferior quality.
Therefore, there has been a need to provide mechanical music movements of normal mechanical configurations, which can control and actuate one or more light sources, especially for use in displays and toys.